


The Darkest Things Inside

by storming_wolf



Category: Supernatural
Genre: Angel Soulbonds, Angel/Demon Sex, Angelic Grace, Blasphemy, Demon Dean Winchester, Dubious Consent, Established Castiel/Dean Winchester, Eye Sex, Fledglings, M/M, Mpreg, Parenthood, Protective Dean Winchester, Soul Bond, Soulmates, Unresolved Romantic Tension, i'm sorry god, literally this is just pure blasphmey
Language: English
Status: In-Progress
Published: 2014-10-25
Updated: 2014-10-26
Packaged: 2018-02-22 13:56:03
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 2
Words: 3,171
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2510207
Author URL: https://archiveofourown.org/users/storming_wolf/pseuds/storming_wolf
Summary: <blockquote class="userstuff">
              <p>While trying to cure Dean, Dean tricks Castiel into having sex with him. Feeling betrayed and not wanting it to ruin their already frayed relationship, Castiel keeps it from Dean once he's cured until he starts getting sick and discovers that he's pregnant with a baby that could only belong to the demon.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> This plot just kinda happened so lets see where this goes.
> 
> In this chapter, Dean does take advantage of Cas so if that's not your cup of tea, you can skip the line break or wait till chapter 2 since the line break isn't much

Cas had carried Dean to the bunker while Sam went to go get more blood. Cas watched him pace in the pentagram.

“Got your wings back, angel?” Dean smirked at Cas. Cas stared silently. “Come on, angel. You know I love our talks. Talk to me.”

“You are a manipulative demon, and you are not Dean,” Cas said. He watched his black eyes turn green.

“C’mon Cassie. Its still me...deep down,” Dean crossed over the pentagram and pulled on Cas’ arm, pulling the angel flush against his body. “It’s still me.”

Dean captured Cas’ lips and undid his belt buckle, pushing his pants down. Cas tentatively placed his hand on Dean’s shoulder, at first as an attempt to push Dean away, but the demon put his hands on either side of Cas’ face and pulled him into the kiss deeper, doing that thing with his tongue that made Cas weak in the knees. He tightened his grip on the angel to keep him upright. Cas’ hands fell on Dean’s chest, eventually trailing under his unbutton shirt to push it off, threading his hair through Dean’s thick hair. Dean’s mouth went down to Cas’ neck as he undid the buttons of his shirt, pushing off the shirt and his trench coat.

Cas was breathing heavily against Dean’s mouth as the demon forced him against the wall. Cas removed Dean’s shirt and tossed it to the side. Dean forced Cas’ hands above his head and bit the angel’s lip, his hand forcing his mouth open by squeezing his cheeks. Dean kissed down his chest, dragging his teeth against the skin as Cas’ breathing grew heavier. Dean got on his knees and took his dripping cock in his hand.

“It’s been so long since I did this, hasn’t his angel?” Dean teased the underside of Cas’ throbbing erection, the angel’s hands falling to Dean’s hair.

“I…” Cas threw his head back and moaned as Dean took his cock in his mouth. Dean hollowed his cheeks as he took Cas all the way into his mouth, the demon’s nose nuzzling against the hairs at the base of the angel’s cock. Dean looked up at Cas, who had his head thrown back from the pleasure. “Dean…”

Dean pulled off of his cock, making a loud pop as he did and taking a deep breath before sucking him some more. Dean kissed down his length from his head down to his balls.

“Ahh~Dean!” Cas bit his lip as Dean took his balls into his mouth, doing sinful things to them with his tongue. Dean spun Cas around and made him arch his back with his hands against the wall. He slapped his ass, leaving a red handprint on the pale skin.

“Dean, we should talk about thIS~” Cas moaned as Dean began rimming him. He slipped in a finger and Cas was coming with his name on his lip. Cas tried to take a moment to recover from the orgasam, but couldn’t as Dean  pushed him up the wall and forced his cock into his ass.

“DEAN!!!” Cas hit his head on the wall and felt dizzy as Dean held his hips down and fucking roughly into him. Dean forced his mouth onto his and chuckled darkly once he came inside of him.

“You’re so easy, angel,” Dean chuckled as he held his arms down and wrapped his other had around Cas’ neck, forcing the angel to look into his black eyes. “C’mon Cassie, I expected a challenge.”

Cas struggled to gain dominance over the demon. He tried to turn away from him and tried to break from his grasp. “LET ME GO!”

“What's the matter? My little angel afraid of the dark?” Dean chuckled darkly. Cas realised there was nothing holding his legs down, so he kneed Dean in the side and kicked his legs from under him. He threw holy water on his face and constrained him to the chair. Castiel snapped his fingers and they were fully clothed again. Dean’s eyes remained black as Cas left the room.

“Come back, angel. By the way you were screaming, I coulda sworn you wanted it,” Dean yelled after him.

Cas just sat outside of the dungeon and cried until Sam got back.

* * *

“You gonna tell me what happened while I was gone?”

Dean was unconscious from the treatment and Cas was staring at his feet, avoiding looking at Dean and Sam.

“Nothing happened,” Cas whispered.

“Then why is there white bodily fluids all over the wall?” Sam asked. Cas stared at the ground.

“He tricked me,” Cas whispered. “I don’t know how I fell for it, Sam. It’s just...when he kissed me...He hasn’t kissed me like that since before purgatory. I wanted to believe that it was Dean, that he wasn’t mad at me anymore, that I hadn’t done anything to ruin everything in the world. I just...I wanted Dean to be in love with me again.”

“Cas, he still loves you,” Sam said. “Before this happened, there would be nights where he was drunk off his mind, crying over how he screwed things up between you two. He wanted to fix things between you two, but all of this happened. I...when things calm down, when he’s human again, you should talk to him.”

“He took advantage of me…” Cas said. “I’m going to remember that for the rest of eternity, Sam. I….I’m so fucking stupid.”

“Hey, hey, shhh. It’s okay Cas,” Sam said.

“I’m not sure if it’s ever gonna be okay,” Cas said before leaving the dungeon.

* * *

 Cas knocked on Dean’s door and waited for his answer.

“Yeah?” Dean’s voice was hesitant. Cas opened the door and saw Dean sitting on the bed. He looked like he had seen hell.

“You look terrible,” Cas said honestly.

“Y’know, it wouldn’t kill you to lie every now and again,” Dean adjusted himself on the bed. Cas carefully got closer to him

“No, it wouldn’t kill me...I’d...just...you,” Cas had no idea what he was trying to say.

“Forget it,” Dean said. He stood up. “Well, you on the other hand. You...lookin’ good. So, are you back?”

“At least temporarily,” Cas started. “It’s a long story. Crowley...stolen grace…Another time.”

“Well thank you, for steppin’ in when you did,” Dean said. “I...I didn’t do anything to hurt you or Sam, did I?”

“I don’t know the entirety of what you did as a demon, but you did chase him with a hammer and try to kill him,” Cas said. “But we know that wasn’t you. Well, at least not all you.”

“I tried to kill him…” Dean repeated it to himself. “I didn’t hurt him,or you, did I?”

“No, we’re okay,” Cas lied. He still couldn’t look Dean in the eyes.

“I...I’m sorry,” Dean said. He put a hand on Cas’ arm. “For everything that’s gone down between us these past few years.”

“It takes two to destroy the world,” Cas said, making Dean smile.

“Can we..Can we forget everything? All the fights, all the pain, all of it, and just go back to what we had?” Dean asked. Cas nodded.

“But..Let’s take it slowly this time,” Cas said. “I’ve missed you.”

“I’ve missed you too,” Dean pulled Cas into a kiss that led to the bed. Cas stopped Dean as his hands went to his belt.

“N-Not tonight,” Cas stuttered. “Let’s just lay here.”

Dean was taken aback at first, but slipped his arms around Cas’ waist and falling asleep with the angel in his arms. Cas stared at the ceiling trying to figure out if things would ever be the same between him and Dean.


	2. Chapter 2

**Notes for the Chapter:**

> Whoa I didn't expect all these kudos and stuff wow thanks I'm humbled! To be honest this was supposed to be a one-shot but I thought if it was good enough I'd continue and your kudos fueled this chapter! I'm going back to fix the errors on the last chapter cause I wirte on Google Docs from my iPod and autocorrect gets me and sometimes it doesnt catch some of my errors.
> 
> And Cas is doing human things like sleeping and showering and eating because he's trying to reserve his grace as much as possible.

Dean woke up and found himself tangled in Cas' limbs. Cas was flush against his back, an arm and leg thrown lazily over his body. Dean smirked as he felt the angel's morning wood hard against his back. Dean slowly nudged Cas off of him but felt the grip tighten as they were rolled over.

"You're not leaving me that easily," Cas smiled, leaning up to kiss him softly.

"Mornin' Cas," Dean whispered against his lips. They lazily kissed for a while before Dean began to kiss down his chest. Cas gasped as he felt Dean's tongue reach the trail of pubic hairs in his stomach. Cas awkwardly pushed Dean away.

"I have to shower," Cas left a quick peck on Dean's lips before rushing into the hall. Dean sighed and pulled on a pair of sweatpants before heading to the kitchen. It had been a month since he had been cured and Cas had been acting strange ever since, especially when they were alone. They'd get in the mood, Cas would do that thing to the spot behind his ear that drove him crazy, and they would both get hard, but as soon as Dean started to initiate sex, Cas would panic and tell him that he wasn't in the mood. He respected Cas' wishes, but he was thrown off by it and really sexually frustrated.

As Dean watched the coffee brew, he tried to think back to the last time he and Cas had had sex. It was not too long after Cas initially stole an angel's grace. They were still not on speaking terms of their relationship, and the sex had been emotional and messy in the back of the Impala. The time before that is when Dean visited while on a case, and it was more of a regretful heat of the moment fuck in the storage room of the Gas n' Sip that Cas worked at. Maybe that's why Cas was being reluctant to dive back into having sex.

While Dean tried to think of what was still unspoken between their relationship, Cas wrapped a towel around himself as he stepped out of the shower. He looked in the mirror and tried to decipher why he felt so dirty. He tried to find another reason besides Dean raping him, but he couldn't. Everytime Cas wanted to have sex, he remembered everything that demon Dean said and did to him and freaked out. He tried to tell himself that it was okay, that he'd recover eventually. He pulled on Dean's clothes that he had let Cas wear and got lost in the scent of Dean. The mix of his cologne, motor oil, a hint of pie, and everything so Dean brought him back from his worried thoughts and it confused him how he thing that brought him distress also bought him solace.

Cas returned to Dean's room and lied on his bed, taking in everything Dean about the room. Eventually, Dean came into the room with two cups of coffee, handing Cas his. The angel savoured the drink as he took a small sip before placing it on the nightstand next to Dean's. He cuddled into the hunter's side. Before they knew it, Cas was straddling Dean and making out with him. Dean slipped his hand down Cas' pants and Cas pushed himself off of Dean.

"Alright, what's up?" Dean asked.

"What do you mean?" Cas asked.

"I know the last time we had sex wasn't all that great cause we weren't on good terms, but you've been givin' me mixed signals about what you wanna do," Dean said. "I respect it if you don't wanna have sex but just give me some insight as to why I'm givin' myself blue balls over here."

"I...I..." Cas stuttered. He leaned over Dean and threw up on the floor on the side of the bed. Dean freaked because Cas essentially projectile vomited last nights burgers all over the floor.

"Whoa, baby! You okay?" Dean asked.

"I need to-" Cas got up and tried to go to the bathroom, but as soon as he was upright the nausea hit him again and he fell to his knees, getting sick on the floor again. Dean quickly swept the angel into his arms and carried him to the bathroom where Cas threw up three more times.

Once the wave of nausea was over, he collapsed into Dean's chest and took deep breathes. Dean handed him a water bottle and ran his fingers through his hair. Cas shakily drank the water and found even the beating of Dean's eyelashes too loud. Dean carried him to the room adjacent to his and laid Cas on the bed.

"Are you okay?" Dean asked. Cas shook his head no and curled into a ball. Dean felt his forehead. "Is it your grace? What's happening?"

"I'm not sure," Cas whispered. "I just don't feel good and I want to sleep for a while."

"I'll clean up our room, just sleep here," Dean said.

Cas put a hand on his stomach, trying to settle the pain when it suddenly intensified to a severe, sharp pain. He screamed into a pillow as he felt his soul and grace rip from within. The pain was so immense that he saw black spots until he didn't see anything at all.

* * *

"Cas? Cas? Cassie?" Dean shook the angel. His eyes popped open and he looks at Dean.

"Oh my god, you had me worried," Dean kissed him gently and helped him sit up. Cas noticed that he was in the bunker's infirmary, another room they had discovered recently.

"How'd I...what's going on?" Cas asked.

"What do you remember?" Dean asked.

"I threw up this morning," Cas said.

"This morning? Cas that was three days ago," Dean said. "What was that?"

"I'm not sure," Cas admitted. He stood up shakily and followed Dean to the kitchen where Sam was making breakfast.  As soon as the smell of eggs hit Cas' nose, he took off for the bathroom. Dean raced after him and Sam came in with some water.

"It's like you're pregnant or something Cas,"  Sam joked halfheartedly. Cas frowned as he placed a hand on his stomach and looked away from the brothers.

"Cas? What are you thinking?" Dean asked in concern. The angel's mind raced as he tried to figure out what that pain was before he had passed out a few days ago. Then he felt _it_.

"No," Cas whispered. He pushed past the brothers and went into his room that had gone unused for a long time. He sat against the door, sobbing into his knees.

"Cas? "

"Go away Dean," Cas said.

"I can't. Something's wrong with you and I care because...because you're my boyfriend, Cas, and I love you and I know I don't tell you enough but I really do baby," Dean said. Even when they first got together after the apocalypse, Dean never defined the relationship.

Cas opened the door, afraid of what he had to tell him.

"What's going on?" Dean asked. Cas lead him to the bed.

"There is an abomination inside of me," Cas whispered.

"What?" Dean asked.

"There is a caphillim inside of me!" Castiel yelled.

"What's a caphillim? Cas, is it serious?!" Dean asked.

"A caphillim...it's never ended well. Back when I was just a fledgling, Gabriel told me about the caphillim and how deadly they were. Fledglings drain some grace, not enough harm an angel, nephillim drain nearly all of an angel's grace," Cas started. "But caphillim, they can kill a healthy angel and I'm not even at full capacity."

"I'm lost Cas, what is a caphillim and how did it get in you?" Dean asked.

"A caphillim is the baby of an angel and a demon and it got in me when...w-when we had sex," Cas didn't look at Dean.

"Cas we haven't had sex since Janu...C-Cas? Did we...when I was...?" Dean asked as he thought through what he was just told. Cas nodded. "Did...did you completely consent to it?" Cas was quiet for a minute.

"I didn't exactly make an effort for you to stop..." Cas went on.

"Cas! Tell me the truth! Was it something you wanted to happen?" Dean asked.

"No..." Cas whispered. Dean stressfully ran his hand through his hair. "Don't blame yourself-"

"Tell me the full story and I'll decide if I can blame myself or not," Dean said.

"We were in the dungeon. Y-Your eyes went green and you told me it was you and I knew I should talk to you but before I knew what was happening you had me against the wall and I gave into it because you hadn't kissed me like that in so long, I made myself forget that you weren't you. Then your eyes went black and I...."

"Tell me Cassie, please," Dean's voice was soft.

"I started screaming for you to let me go and y-you laughed," Cas felt tears fall and he tried to stop himself from crying. Dean pulled him into a tight hug.

"I'm so sorry Cas, oh my god I'm sorry baby," Dean whispered. "What are we going to do about the baby?" Cas curled into Dean's side.

"I feel it. It's soul is so bright but twisted with darkness. I haven't felt a soul so bright and strong since our soul bond," Cas said.

"But the darkness..." Dean asked.

"It's like...like a stain on a clean shirt," Cas' face seemed concentrated. "We can't kill him."

"Cas , it's gonna kill you!" Dean said.

"He has hope! He has whatever small amount of humanity that was in you when you were being cured, Dean we can save him," Cas insisted.

"But can we save you?" Dean asked.

"I've made peace with my fate," Cas said.

"What's that supposed to mean?" Dean asked.

"We're not killing our son," Cas said.

"So we kill you? Cas, that thing isn't our son, it's a monster. We kill monsters," Dean said.

"No, we try to save them like we saved you!" Cas retorted.

"Well you should've killed me!" Dean yelled. "We wouldn't have this problem if you did."

"Killing you was a last resort and it will be the same for our son," Cas said. He took Dean's hand and forced him to feel the soul growing inside of him. It was everything good and evil about both of them.

"This doesn't happen by mistake Dean. The only way the angelic side could be formed is if it was a soulmate. There has never been a caphillim formed with a soulmate which is why I have hope for him," Cas explained.

"What about you? How do we keep you alive?" Dean asked.

"We store my grace once the baby receives enough. Once he is born, I can restore it and use it to remove the traces of evil. It may not work, but its worth a shot," Cas said. Dean put a hand on Cas' stomach again. He could see his son's life. He could feel his soul attach to the unborn baby.

"Do you really think it'll work?"  Dean asked.

"If there's one thing I learned in the past six years, it's that nothing is impossible for a Winchester."

**Notes for the Chapter:**

> So I came up with Caphillim while researching the names of human/angel babies and demon/angel babies which was Nephillim and Cambion, respectvilly. I was gonna go with like a mix of the etymology of the two but then I remembered that I only got a B- in etymology so better not. I'm, in Destiel fashion, making up the mythology of a caphillim as I go, so I hope you like it


End file.
